In the proposal [1]}, the inflaton \(y\)  was identified with the superpartner of a state that mixes with a R-handed neutrino entering in the so-called \(\lambda _6\)  coupling of the flipped \(SU(5)\)  superpotential [2]} that provides neutrino masses upon the GUT symmetry breaking. The inflaton can then decay in R-handed neutrinos reheating the universe and there is an interesting connection with the neutrino mass generation. This possibility is compatible with the GUT symmetry breaking occurring by a first order transition at a critical temperature which is lower than the inflation scale [1]}. As a result, \(SU(5)\times U(1)\)  remains unbroken during the inflationary era.
